brocklanders
New Member
I bought a 2000 260 bow rider, and the freeze plugs are blown out on it. The mechanic said he may have to pull the engine to put one of the plugs in. Is that normal?
Pull motor to install freeze plugs?
- Thread starter brocklanders
- Start date
Skybolt
Well-Known Member
- Nov 11, 2014
- 6,472
- Boat Info
- Reel Nauti
460 EC
- Engines
- Detroit 6v92TA
(Low profile's)
Alison Gears
Westerbeke
12.5kw Genset
I would make sure the rest of the engine is good before that. Like do a leak down test and make sure nothing else is damaged when it froze. Unless this is to replace a rusted one. The exhaust must be removed either way. So not sure where it is located. There are a few on the engine. But if it is unaccusable then you don't have a choice.
Yes, some of the "casting" plugs are near impossible to get in without pulling the engine. Take a look down in your engine bay at the access and you'll see 
They are "casting" plugs, not freeze plugs - sometimes you get lucky... really lucky... and the casting plugs pop out before internal damage is done. But that is not their intended purpose.
As noted... check internally before pulling the engine. However, a competent mechanic with the right setup can do this in a few hours, give or take - so it's not a "huge" deal.
They are "casting" plugs, not freeze plugs - sometimes you get lucky... really lucky... and the casting plugs pop out before internal damage is done. But that is not their intended purpose.As noted... check internally before pulling the engine. However, a competent mechanic with the right setup can do this in a few hours, give or take - so it's not a "huge" deal.
- Sep 25, 2016
- 1,257
- Boat Info
- 300 Sundancer 1994, trailered tri-axle LoadRite roller
- Engines
- Mercruiser 5.7 260HP Alpha One Gen II, twin
brocklanders
New Member
The block is okay! Needs a circulation pump and new freeze plugs, but the block is okay.
You popped all the casting plugs and had no damage? Play the lottery tonight.
brocklanders
New Member
quite lucky!
I think we are chasing ghosts . Never heared of popping the plugs without freeze cracking the block
DaveKamp
Active Member
- Jun 9, 2021
- 189
- Boat Info
- 1970 SRV180, '77SRV220CC, 76 SRV-240FB, another SRV180
- Engines
- Mostly MerCruisers with R-MR-Alpha drives
Frozen blocks are very common failures north of I-70... and being significantly north of that range, I've seein it. For six springtimes in a row, I pulled drives and engines that had not been winterized in time, usually around ten every May. Exactly zero in every ten survived... those that looked good, once opened, had absolute failure inside.
Here's the physics facts:
- When water initially freezes, it forms a crystalline structure that expands around 9-10%.
- As water freezes, the crystalline structure's density DECREASES, causing the ice formation to start at the top, and proceed downward.
- As the contained pressure of liquid water increases, the freezing temperature DECREASES, and the resultant expansion volume INCREASES.
- The expansion FORCE for freezing water STARTS at 25,000psi... and levels off around 114,000psi.
If you've got frost plugs popped out on a BBC, there's thousands of tiny internal fractures in the block that you won't see, but you'll find once you advance the throttle. Not a big deal, as the engine will shut itself down once the main bearing saddles and crank throws exit through the bilge.
While you have the engine out, it'll be easy to replace the long block, and as a bonus, you'll have a complete rotating assembly, camshaft, valves, and fasteners that will be unscathed. That being said, your intake manifold, exhaust manifold, riser elbows, oil cooler, thermostat housing/cover, thermostat, and water hoses are all damaged, too. Probably the hose to your outdrive or transmission (if you have them), and your raw water heat exchanger (if you have closed cooling). Depending on how it came to be frozen, you may be in for a transmission (if it has a water cooling jacket) or an outdrive (if it had water trapped in it's passages).
It is very common for shysters to sell boats with blown out frost plugs, and tell you that there's no damage. They're lying.
Here's the physics facts:
- When water initially freezes, it forms a crystalline structure that expands around 9-10%.
- As water freezes, the crystalline structure's density DECREASES, causing the ice formation to start at the top, and proceed downward.
- As the contained pressure of liquid water increases, the freezing temperature DECREASES, and the resultant expansion volume INCREASES.
- The expansion FORCE for freezing water STARTS at 25,000psi... and levels off around 114,000psi.
If you've got frost plugs popped out on a BBC, there's thousands of tiny internal fractures in the block that you won't see, but you'll find once you advance the throttle. Not a big deal, as the engine will shut itself down once the main bearing saddles and crank throws exit through the bilge.
While you have the engine out, it'll be easy to replace the long block, and as a bonus, you'll have a complete rotating assembly, camshaft, valves, and fasteners that will be unscathed. That being said, your intake manifold, exhaust manifold, riser elbows, oil cooler, thermostat housing/cover, thermostat, and water hoses are all damaged, too. Probably the hose to your outdrive or transmission (if you have them), and your raw water heat exchanger (if you have closed cooling). Depending on how it came to be frozen, you may be in for a transmission (if it has a water cooling jacket) or an outdrive (if it had water trapped in it's passages).
It is very common for shysters to sell boats with blown out frost plugs, and tell you that there's no damage. They're lying.
